Diabetes Mellitus (type 2)

Question 1

Definition

Answer 1

· Characterised by increased peripheral resistance to insulin action, impaired insulin secretion and increased hepatic glucose output

Question 2

Aetiology/Risk factors

Answer 2

· Genetic and environmental

· There are a few monogenic causes of diabetes (e.g. MODY, mitochondrial diabetes)

· Obesity increases the risk of T2DM (due to the action of adipocytokines)

· Diabetes can happen secondary to:
o Pancreatic disease (e.g. chronic pancreatitis)
o Endocrine disease (e.g. Cushing’s syndrome, acromegaly, phaeochromocytoma, glucagonoma)
o Drugs (e.g. corticosteroids, atypical antipsychotics, protease inhibitors)

Question 3

Epidemiology

Answer 3

· UK Prevalence: 5-10%

· Asian, African and Hispanic people are at greater risk

· Incidence has increased over the past 20 yrs

· This is linked to an increasing prevalence of obesity

Question 4

Presenting symptoms

Answer 4

· May be an incidental finding

· Polyuria

· Polydipsia

· Tiredness

· Patients may present with hyperosmolar hyperglycaemic state (HHS)

· Infections (e.g. infected foot ulcers, candidiasis, balanitis)

· Assess cardiovascular risk factors: hypertension, hyperlipidaemia and smoking

Question 5

Signs on physical examination

Answer 5

· Calculate BMI

· Waist circumference

· Blood pressure

· Diabetic foot

Question 6

Signs on physical examination (diabetic foot)

Answer 6

· Diabetic foot (ischaemic and neuropathic signs)

o Dry skin
o Reduced subcutaneous tissue
o Ulceration
o Gangrene
o Charcot's arthropathy
o Weak foot pulses

Question 7

Signs on physical examination (skin changes)

Answer 7

· Skin changes (RARE):

o Necrobiosis lipoidica diabeticorum (well-demarcated plaques on shins or arms with shiny atrophic surface and red-brown edges)

o Granuloma annulare (flesh-coloured papules coalescing in rings on the back of hands and fingers)

o Diabetic dermopathy (depressed pigmented scars on shins)

Question 8

Investigations (diagnosis)

Answer 8

· T2DM is diagnosed if one or more of the following are present:

o Symptoms of diabetes and a random plasma glucose > 11.1 mmol/L

o Fasting plasma glucose > 7 mmol/L

o Two-hour plasma glucose > 11.1 mmol/L after 75 g oral glucose tolerance test

Question 9

Investigations (monitor)

Answer 9

o HbA1c
o U&Es
o Lipid profile
o eGFR
o Urine albumin: creatinine ration (look out for microalbuminuria)

Question 10

Management plan (glycaemic control)

Answer 10

· Glycaemic control - there is a step-wise approach to the management of T2DM:

o At diagnosis: lifestyle + metformin

o If HbA1c > 7% after 3 months: lifestyle + metformin + sulphonylurea

o If HbA1c > 7% after 3 months: lifestyle + metformin + basal insulin

o If HbA1c > 7% after 3 months and fasting blood glucose > 7 mmol/L: add premeal rapid-acting insulin

o NOTE: sulphonylurea may be given as a monotherapy if patients cannot tolerate metformin

o NOTE: pioglitazone (thiazolidinedione) may also be given alongside metformin and a sulphonylurea

Question 11

Management plan (screening for complications)

Answer 11

o Retinopathy

o Nephropathy

o Vascular disease

o Diabetic foot

o Cardiovascular risk factors (e.g. blood pressure, cholesterol)

Question 12

Management plan (other)

Answer 12

· Pregnancy - requires strict glycaemic control and planning of conception

· Hyperosmolar Hyperglycaemic State - management is similar DKA
o Except use 0.45% saline if serum Na+ > 170 mmol/L

Question 13

Possible complications (hyperosmolar hyperglycaemic state)

Answer 13

o Due to insulin deficiency
o Marked dehydration
o High Na+
o High glucose
o High osmolality
o No acidosis

Question 14

Possible complications (neuropathy)

Answer 14

o Distal symmetrical sensory neuropathy
o Painful neuropathy
o Carpel tunnel syndrome
o Diabetic amyotrophy
o Mononeuritis
o Autonomic neuropathy
o Gastroparesis (abdominal pain, nausea, vomiting)
o Impotence
o Urinary retention

Question 15

Possible complications (nephropathy)

Answer 15

o Microabuminuria
o Proteinuria
o Renal failure
o Prone to UTI
o Renal papillary necrosis

Question 16

Possible complications (retinopathy)

Answer 16

o Background
o Pre-proliferative
o Proliferative
o Maculopathy
o Prone to glaucoma, cataracts and transient visual loss

Question 17

Possible complications (macrovascular)

Answer 17

o Ischaemic heart disease
o Stroke
o Peripheral vascular disease

Question 18

Prognosis

Answer 18

· Good prognosis with good control

· Pre-diabetes can be diagnosed based on fasting blood glucose and oral glucose tolerance test:
o Impaired Fasting Glucose (IFG) = fasting blood glucose 5.6-6.9 mmol/L
o Impaired Glucose Tolerance (IGT) = plasma glucose level of 7.8-11.0 mmol/L measured 2 hrs after a 75 g oral glucose tolerance test

· People with IFG or IGT are at high risk of developing type 2 diabetes